AtCAF-1 mutants show different DNA damage responses after UV-B than those activated by other genotoxic agents in leaves

MAULIÓN, EVANGELINA; GOMEZ, MARÍA SOL; BUSTAMANTE, CLAUDIA ANABEL; CASATI, PAULA

PLANT, CELL AND ENVIRONMENT (PRINT)

WILEY-BLACKWELL PUBLISHING, INC

Año: 2019 vol. 42 p. 2730 - 2745

0140-7791

CAF-1 is a histone H3/H4 chaperone that participates in DNA and chromatin interaction processes. In this manuscript, we show that organs from CAF-1 deficient plants respond differently to UV-B radiation than to other genotoxic stresses. For example, CAF-1 deficient leaves tolerate better UV-B radiation, showing lower CPD accumulation, lower inhibition of cell proliferation, increased cell wall thickness, UV-B absorbing compounds and ploidy levels; while previous data from different groups have shown that CAF-1 mutants show shortening of telomeres, loss of 45S rDNA and increased homologous recombination, phenotypes associated to DNA breaks. Interestingly, CAF-1 deficient roots show increased inhibition of primary root elongation, with decreased meristem size due to a higher inhibition of cell proliferation after UV-B exposure. The decrease in root meristem size in CAF-1 mutants is a consequence of defects in programmed cell death after UV-B exposure. Together, we provide evidence demonstrating that root and shoot meristematic cells may have distinct protection mechanisms against CPD accumulation by UV-B, which may be linked with different functions of the CAF-1 complex in these different organs.